Functional electrical stimulation (FES) is a method of restoring functional gait (walking) to paralyzed individuals. In FES, certain leg muscles are stimulated with an electrical stimulator. Electrical signals produced by the electrical stimulator are conveyed to the leg muscles by electrodes. The electrodes can either be placed directly on the skin of the individual over the muscles or implanted within the muscles. Depending upon the individual's condition, a single leg or both legs can be stimulated. By controlling the electrical signals provided to the leg muscles with a computer, walking can be produced.
In some current FES systems, the individual initiates the stimulation of leg muscles by hand actuated switches. In the case of a hemiplegic (paralysis of one side of the body) where one leg is functional, a switch can be manipulated to initiate intermittent stimulation and movement of the paralyzed leg in tandem with the functional leg to enable the individual to walk. In the case of a paraplegic, the left and right leg muscles can be alternately stimulated to produce walking by manipulating switches.